French President Emmanuel Macron speaks at the European Parliament in Strasbourg, France, on Tuesday. (Jean Francois Badias/AP)

ALTHOUGH HIS audience was the European Parliament, French President Emmanuel Macron articulated truths on Tuesday that resonate for the entire globe. Nationalism and authoritarianism are on the march. Democracy as an ideal and in practice seems under siege. The United States, traditionally a beacon for freedom, has dimmed the light, at least for a time.

Mr. Macron filled the gap with a thoughtful and bracing warning.

He declared that Europe is being torn by the rise of “national selfishness and negativity” and a growing “fascination with the illiberal.” In particular, he warned of the kind of anti-migrant authoritarianism on display recently in the Hungarian elections and fashionable among far-right parties in Europe.

But his words also apply more broadly to the surge of illiberalism in Turkey, Egypt, Russia, China, Cambodia, Vietnam, Azerbaijan, the Philippines and Venezuela, among other places, where leaders have actively snuffed out civil society, suborned or faked elections, asphyxiated free expression, ignored rule of law, and repressed basic human rights. Leaders in such countries learn from one another as they refine methods to crush democracy, by banning or restricting nongovernmental organizations, creating laws to single out independent voices as “foreign agents,” imposing censorship on the news and social media, and, most tried and true, jailing those who dissent. They also echo one another’s claims that their imposed order offers a viable alternative to democracy, which can be so unpredictable and messy.

Mr. Macron wisely denounced a “deadly illusion” that “has precipitated our continent toward the abyss” in previous generations: “the illusion of strong power, nationalism, the abandonment of freedoms.” Democracy is not being “condemned to impotence,” he insisted. “Faced with the authoritarianism that surrounds us everywhere,” he declared, “the answer is not authoritarian democracy, but the authority of democracy.”

Mr. Macron, less than a year in office, a leader born after World War II, summoned Europeans not to be complacent about democracy and the need to fight for it. “I do not want to belong to a generation of sleepwalkers. I do not want to belong to a generation that will have forgotten its own past or that will refuse to see the torments of its own present,” he said. “I want to belong to a generation that has decided firmly to defend its democracy.”

Not all efforts by the United States to promote and defend democracy have been successful, but that is no reason to give up. Mr. Macron’s address was a needed summons. Irresponsibly, President Trump cannot find a voice for such essential principles. In this vacuum, it would be reassuring to hear German Chancellor Angela Merkel be more outspoken, as well as others who lead democratic societies. The danger of sleepwalking is real. So are the consequences of losing this battle, which would consign tens of millions of souls to live in a darker world without the dignity to think, talk and be ruled as they choose.